Combination, deasphalting, phenol treating, and dewaxing process



Oct. 19, 1954 PACKIE COMBINATION, DEASPHALTING. PHENOL.

TREATING. ANDvDEWAXING PROCESS 2 Sheets-Sheet l Filed Oct. 27, 1950 Oct.19, 1954 J, W PACKH; 2,692,222

COMBINATION DEASPHALTING PHENOL TREATING, AND DEWAXING PROCESS FiledOct. 27, 1950 2 Sheets-Sheet 2 dmngm E330/S mmm mm ummzmzow mzowa OP Yes d .541%4 zoom QOFDJOW O @lohn LQfPcLcEL'Le, [Snventov- @ggz/'UlCLLt/orneg Patented Oct'. 19, 1954 COMBINATION, DEASPHALTING, PHENOLTREATING, AND DEWAXING PROCESS John W. Packie, Maplewood, N. J.,assigner to Standard Oil ration of Delaware Develo pment Company, acorpo.-

Application October 27, 1950, Serial No. 192,404

9 Claims. 1

The present invention is concerned with an improved deasphalting, phenoltreating and dewaxing process. The invention is more particularlyconcerned with an improved lubricating oil operation wherein theprocessing steps of deasphalting, dewaxing and phenol treating arecombined. In accordance with the specific adaptation of the presentinvention a distillate feed stream from a conventional vacuum asher aswell as a residuum from the vacuum flasher are separately introducedinto a combination treater tower. The residuum is countercurrentlytreated with propane or an equivalent deasphalting solvent in the lowerportion of the tower for deasphalting. The deasphalted stream passes upthe tower being partially treated with phenol or an equivalent solventbefore combining with the distillate feed for final quality improvement.The raffinate mixture containing phenol as well as propane passesdirectly to a conventional dewaxing plant. The effluent wax mixture fromthe dewaxing plant combines with the extract-asphalt solution beforesolvent recovery. The dewaxed oil mixture is separately processed fordewaxed oil recovery. The solvent recovery from this stream is partiallyintegrated, in a novel fashion, with the solvent recovery from theeXtract-asphalt-wax solution. Propane is used for stripping phenol fromthe flashed oil streams.

It is well known in the art to treat feed oils, particularly distillatefeed oils, with various solvents in order to separate the relativelymore aromatic type constituents from the relatively more parafiinic typeconstituents. Solvents generally employed are phenol, various cresols,sulfur dioxide and the like. In these operations the feed oil is usuallycontacted with the selected solvent such as phenol either in acountercurrent treatingr operation or in a multi-stage batch operationunder temperature and pressure conditions to secure phase separation. Asa matter of practice, the oil to be treated is usually introduced intoone end of a countercurrent treating zone while the solvent or solventmixture is introduced at the other end. The solvent and oil flowcountercurrently under temperature and pressure conditions whereby phaseseparation is secured. The solvent rich or solvent extract phase iswithdrawn from one end of the countercurrent treating zone, while thesolvent poor or the raffinate phase, comprising the more paramnic typeconstituents, is withdrawn from the other end of the treating zone. Therespective streams are then handled in a manner to segregate the solventfrom the oil.

It is also known in the art to conduct a light hydrocarbon deasphaltingprocess. In a process of this character, an oil phase or feed streamcontaining asphaltic type constituents is mixed with a light hydrocarbonsolvent such as, for example, liquid propane under temperature andpressure conditions whereby the asphaltic type constituents are thrownout of solution. After separation of the asphaltic type constituentsfrom the deasphalted oil, the respective streams are handled in a mannerto recover the solvent.

It is also known in the art to remove waxy constituents from a parafnictype oil containing the same in order to improve the quality of the oil.This is usually accomplished by employing a dewaxing solvent such aspropane, methyl ethyl ketone or a similar dewaxing solvent. Inoperations of this type, the waxy oil and the solvent are usually heatedto a temperature to secure a single phase or substantially completemiscibility of the ingredients. The waxy mixture is then chilled inorder to precipitate Wax particles or crystals from the solution. Thechilled mass is filtered in order to seggregate the wax particles andfurther handled in a manner to recover the dewaxing solvent, and tofurther rene the dewaxed oil and the segregated waxes.

It has now been discovered that an improved combination process may beemployed providing the respective feed streams are handled in aparticular manner. The present invention may be readily understood byreference to the drawings illustrating one embodiment of the same.Figure I illustrates the operation with respect to the handling of thefeed streams and the respective solvents. Figure II illustrates theoperation particularly with respect to one method of handling thesolvent recovery operations of the respective streams.

Referring specifically to Figure I, a distillate hydrocarbon feed isintroduced into about the middle section of a combination treater zone'13 by means of line 10. If desired and under certain conditions it maybe desirable to introduce the feed at a point between the middle thirdand upper third of zone 13 by means of line ll.

A residuum hydrocarbon feed is introduced into zone 13 by means of line'I2 at a point between about the middle third and the lower third of thecombination treater zone.

In accordance with the present invention, a solvent having apreferential selectivity for the more aromatic type constituents, as,for example, phenol, furfural, nitrobenzene, various organic nitrates,acetates and other esters, and the like, is introduced into the top ofzonel'by means of line 8l. These so-called polar solvents `may be usedin admixture or modified by various modifying solvents such as Water andthe like. The preferred solvent comprises phenol. Also in accordancewith the present invention it is preferred to introduce a portion of thephenol or equivalent solvent into approximately the middle of zone 13 bymeans oi line 80.

A light hydrocarbon deasphalting solvent as, for example, a liquefiednormally gaseous hydrocarbon such as propane, is introduced into thebottom of zone 13 by means of line B9. Under the conditions of operationa ramnate phase comprising paramnic type constituents, a relativelylarge quantity of propane and a small amount of phenol or equivalentsolvent is removed overhead from zone 13 by means of line 14. Thisstream, if desired, may be combined with additional propane which isintroduced by means of line 11. In accordance with a preferredadaptation of the present invention the stream is passed through acooling zone 290 into a separation zone 20| wherein phase separationoccurs. The solvent-rich phase is withdrawn from separation zone 2D! bymeans of line 202 and re-introduced into the top of zone 13 below thepoint of the introduction of the phenol stream which is introduced intozone 13 by means of line 8l. The oil-rich phase is removed fromseparation zone 20| and introduced into a dewaxing zone 15.

Additional propane may be introduced into dewaxing zone 15 by means ofline 16. This will be necessary providing autorefrigeration is employedin zone 15 in order to make up from the propane of equivalent solventevaporated. The f dewaxing zone may comprise any suitable number andarrangement of stages.

The dewaxed oil solution is removed from zone 15 by means of line 18 andpassed to dewaxed oil solvent recovery facilities 19 in order to removeand recover the solvent from the dewaxed oil. A high quality dewaxed oilfree of solvent is removed from the system by means of line 91 andfurther handled or refined as desired. A stream relatively rich inphenol is removed from Zone 19 by means of line 8d while a streamrelatively rich in propane is removed from zone 19 by means of line 86.

The wax solution segregated in zone 15 is removed by means of line 82and passed to wax solvent removing facilities 83. A stream rich inphenol is removed by means of line B5 combined with the phenol streamremoved from zone 19 by means of line B4 and then introduced into thetop of zone 13 by means of line 8l.

A stream relatively rich in propane is removed from zone 33 by means ofline 81, combined with the propane removed from zone 19 by means of line86 and segregated into two streams. One stream is employed to addadditional propane to the raiinate phase removed overhead from zone 13by means of line 14, while the remaining amount is recycled to thebottom of zone 13 by means of line 89. WaXes substantially free ofsolvent are removed from zone 83 by means of line 9B and further handledor rened as desired.

A solvent extract phase comprising asphaltic constituents is removedfrom the bottom of zone 13 by means of line |02 and introduced intosolvent removing facilities |00. A stream rich in phenol or equivalentsolvent is removed from zone 1GB by means of line 8f3 and recycled tothe top of zone 13. A stream rich in propane is removed from zone |01]by means of line |03 and d combined with a propane stream segregated inzone 19 and 83 and recycled to the bottom oi treating zone 13. A solventfree extract is removed from zone me by means of line lul and furtherhandled or rened as desired.

The above description with respect to Figure I comprises one embodimentof the invention wherein a single deasphalting and solvent treating zoneis utilized and wherein the dewaxing operation is combined with thelother processing steps. The method oi handling the solvent from therespective streams in a manner to efficiently recover and utilize thesame is illustrated by Figure II. Referring specifically to Figure II,the dewaxed oil solution introduced into dewaxed oil solvent recoveryzone 19 is introduced through line l, passed through a heat exchangingzone 12 in order to heat the same, and then introduced into a propanerecovery tower 2 or equivalent means. Temperature and pressureconditions are adjusted to remove overhead from the propane recoverytower 2 a propane stream. A portion of this stream is segregated bymeans of line 6, which comprises a dry propane stream. The remainingpropane is passed through line 5 and handled as hereinafter described.The anhydrous propane segregated by means of line 6 is subsequentlyemployed to wash the wax cake on the filters.

Reflux propane segregated from any desirable source is introduced intothe top zone 2 by means of line 3. An oil solution comprising oilyconstituents and phenol is removed from the bottom of zone 2 by meansor" line i2, and passed to a reboiler means i3. A portion of this streamis recycled to the bottom of zone 2 by means of line d in order tomaintain the desired bottom temperature while the remaining amount isintroduced into the top of the phenol recovery tower or zone l5 by meansof line i4.

The dewaxed oil containing phenol 'flows downwardly in zone l5 andcountercurrently contacts upflowing steam or equivalent stripping vaporswhich is introduced by means of line it. A dewaxed oil free of phenoland propane is removed from the bottom of zone l5 and further handled orrefined as desired. Phenol containing a small amount of propane isremoved overhead from zone l5 by means of line l1 and passed through acondensing zone 51 by means of line 55. The mixture is passed to aseparation zone 56 wherein the condensed phenol is removed by means ofline 25. The vaporous propane is removed overhead rom zone 56,' passedthrough a compressor 5S, and then withdrawn by means of line 59. Thisstream of propane is recycled to the system by means of lines 8B and 8eas shown in Figure I.

The phenol withdrawn from the bottom oi separation zone 56 by means ofline v295 is introduced in the top of zone 13 by means of line 8l. Thedewaxed oil removed from the bottom of zone I5 is identical with thestream removed from zone 19 by means of line Si. The propane removed bymeans of line 5 is condensed and passed to separation zone 9 wherein aphase separation occurs between aqueous phenol and propane. The aqueousphenol is passed to a drier while the propane is recycled to the systemby means of lines 88 and 89 as shown on Figure I.

The wax solution removed from dewaxing plant 15 by means of line 82 ispassed into solvent recovery facilities 83 by means of line 25. The

wax solution is heated in a heating zone 2l and then introduced into thecenter of a propane recovery tower 22.

A stream rich in propane is :removed overhead from zone 22 by means ofline 21, combined with the overhead stream from Zone 2 by means of line5, cooled in zone 26|, and introduced into a separation zone 9. Propaneis removed by means of line El and handled as hereinbefore described.Reflux propane is introduced into Zone 22 by means of line 2.3.

The waxy solution is removed from the bottom of zone 22 by means of line26 and passed to a reboiler ,25. A portion of the waxy solution isrecycled to the bottom of zone 22 by .means of line 24 to maintainbottom temperature while the remainder is withdrawn by means of line 44and preferably introduced into a secondary propane removal tower or zone2lb. Temperature `and pressure conditions in zene 2i|l are adapted toremove the iinal traces of the propane from the wax. The waxy solutionsubstantially vcompletely free of propane is then introduced into phenolrecovery zone l5 by means of line dll. The temperature and pressureconditions in zone 45 are adapted to remove overhead a phenol stream bymeans of line d5. This stream is passed in heat exchange in reboilers ISand t5, and withdrawn from the recovery system by means of line 39. Thisphenol stream is then recycled to zone 'i3 by mea-ns of line 3| as shownin Figure I.

The wax substantially free of phenol is removed from zone i5 by means ofline d8, passed to reboiler dd and returned to zone 55 by means or lined? to maintain the desired bottoms temperature. The wax stream isremoved from zone 45 by means of line :it and introduced to the top ofphenol remover zone 5|. The stream iiows downwardly in zone 5| andcountercurrently con tacts upiiowing steam which is introduced by meansof line 53. A wax product is removed from the bottom of zone 5i, passedthrough'heat exchanger 54, and withdrawn from the system and furtherhandled as desired. This wax stream corresponds to the wax streamremoved by means of line 96, Figure I. Phenol is removed overhead fromzone 5i by means of line 552 and combined with the stream removed fromzone l5 by means of line i? and handled as hereinabove described.

The extract solution introduced into solvent removing facilities Ibi) bymeans of line lili! is handled by means of line Sli, passed through aheat exchanging zone 3i and introduced into the center section .of apropane stripping zone 33. A propane stream is removed overhead fromZone 33 by means of line 35 and combined with the propane removedoverhead from zone 22 by means of line 2l and from Zone 2 by means ofline 5, and handled as hereinbefore described,

An asphalt phase is removed from the bottom of zone 33 by means 0I" line3l and passed to a reboiler 38. A portion of this phase is reintroducedinto zone 33 by means of line 36 to mainn tain bottoms temperature.

The asphalt phase is removed from the bottom of reboiler 38 by means ofline dii and introduced into a secondary propane removing stage 2id,Temperature and pressure conditions are adapted to remove overhead fromzone 2 i 5 propane which is recycled to the system. The asphalt phase isremoved from Vzone Zie and introduced into phenol recovery zone lli bymeans of line i6. A phenol stream is removed from the top of zone 4| bymeans of line 42 and removed from the system by means of line 39 afterpassing in heat 6 exchange inireboilers `25 .and 38. Ias well as inreboiler I3. As described hereinbefore. this phenol stream is recycledto zone 13 by means of line 8|.

A portion of the asphalt phase is withdrawn from the bottom of zone 4|by means of Jline .63; passed through heating zone 62 and thenintroduced into Zone 4| by means of line 6| to maintain bottomstemperature. Withdrawn from the bottom of zone 4| by means of line 6Uand introduced into the top of a vacuum stripper 64 in order to removethe final traces of phenol.

Phenol is removed overhead from zone 64 by means of line 2I6 combinedwith the stream removed overhead from zones I5 and 5| and handled ashereinabove described. Steam is introduced into the bottom of zone 64 inorder to strip the remaining traces of phenol from the asphalt which isremoved by means of line 5 5 and passed through a heating zone 66. Thisstream corresponds to the stream removed by means of line i of Figure I.The invention is broadly concernedwith an improved method for reiiningpetroleum oils boiling in the lubricating oil boiling range. Inaccordance with the present invention a crude oil is processed through avacuum flasher zone rather than through a conventional pipestill orequivalent means wherein a sharp separation is secured. Normally it ispreferred to process in the vacuum fiasher 20 to 40% of the highestboiling crude bottoms. For example, if 35% crude bottoms (atmosphericpressure) is processed, this stream is heated to a temperature in therange of 750 to 300 E'. and then flashed in the vacuum flasher at apressure in the range of 50 to 20.0, preferably at about millimetersabsolute pressure. Under these conditions a distillate fraction boilingin the range of about 600 to 1100 F. is segregated from a residuumfraction boiling above about 900 F.

The two said streams from the vacuum flasher are separately introducedinto the combination treater tower. The residuum is countercurrentlytreated with propane or an equivalent solvent in the lower portion ofthe tower for deasphalting. The bright stock passes up the tower beingpartiaily phenol treated before combining with the distillate feed foriinal quality improvement.

In accordance with the present invention vacuum residuum and wide-cutlube distillate feed stocks are pumped into acombination propanedeasphalting and phenol treating tower. The residuum is separatelyintroduced in the lower portion or the tower being countercurrentlycon-A tacted with propane for deasphalting. The rafnate from theresiduum, i. e., bright stock, passes upward, countercurrent ,to aphenol bearing distillate extract from the upper portion of the tower.The bright stock is thereby partially phenol treated subsequent todeasphalting. The quality-improved bright stock then passes into thedistillate-phenol treating portion of the tower where it combines withdistillate to be further countercurrently treated with phenol. Theextract from the tower contains most of the phenol in solution withpropane, propane rejected asphalt, and the low-quality phenol extractedoil. The raiiinate contains most of the propane with qualitynimprovedoil in solution with soluble phenol.

The raffinate solution is sent directly to a pro-V pane dewaxing plant.The phenol in the raiiinate acts as a wax diluent or solvent, themajority The asphalt phase isY 7.. ofilt passing out ofY the system inthe wax mixture from the filters.

' For the operations of deasphalting, dewaxing',A

and phenol treating, only three solvent-bearing streamsV must beprocessed in recovery equipment. These are the dewaxed oil mixture, thewaxl mixture, and the asphalt-extract mixture. If wax is not required asa separate product, the wax mixture and the asphalt-extract mixture arecombined for solvent recovery.

:The temperatures and pressures utilized in the combination treater zonemay vary appreciably depending upon the characteristics of therespective streams being processed. In general it is preferred that thetemperatures be in the range of about 50 F. to 200 F. and pressures inthe range of 100 to 500 lbs. per square inch gauge be utilized. Asatisfactory temperature is about 120 F. while a satisfactory pressureis about 250 lbs. pe;1 square inch gauge.

l Although phenol is preferred as the solvent, other equivalent solventsmay be utilized. In general the solvent should be selected from thatclass of solvents having a preferential selectivitf,7 for' therelatively more aromatic type constituents as compared to the relativelymore parainic type constituents. Mixtures of these solvents as well assolvent modifying agents such as water and the like may be utilized. Ingeneral the amount of phenol introduced into the top of the treatel` mayrange from about .5 to 5 volumes of phenol per volume of oil. Adesirable solvent to oil ratio is in the range of about 1:1. The amountof phenol introduced in the center of the treater likewise may varyappreciably. In general it should be approximately half the amountintroduced at the top of the Zone.

Any suitable deasphalting solvent may be used other than propanealthough propane or a solvent comprising propane is desirable. Thequantity of propane utilized based on the quantity of total feed is from3 to 15 volumes of propane per volume of feed. A satisfactory amount isabout 6 volumes of propane per volume of feed.

The raninate stream removed overhead from zone 13 will vary appreciablyin composition, generally having a relatively large amount of propanepresent. Under suitable conditions of operation this raffinate streammay comprise about one volume of oil, 1/2 volume of phenol and about 5volumes of propane. In accordance with the preferred embodiment of theinvention this stream is cooled to about 90 F. in order to secure theseparation of a phenol rich phase which is returned to zone 13 asdescribed. The oil phase is then passed to a dewaxing zone wherein thesame is cooled at a predetermined rate in order to precipitate waxcrystals. These crystals are removed from the oil preferably by lteringor other equivalent means. Generally, the waxy .oil' is cooled to atemperature in the range of 20 F. to -50 F. or lower in order to securesatisfactory precipitation of the wax crystals.

The extract solution removed from the bottom of the treating zone willalso vary appreciably in composition. A typical composition of thisstream comprises one volume of oil, about 2 volumes of phenol and about3 volumes of propane. As described, the solvent recovery facilitates forthe dewaxed oil, the wax solution and the solvent extract solution areinterrelated in a manner to secure improved solvent recovery. Thedewaxed oil solution rich in propane and containing a relatively smallVamount of phenol is processed by means of a phenol recovery zone and apropane recovery zone. The propane is removed in an initial zone, thepressure of which will vary from to 300 lbs. and higher while thetemperature may vary from 200 to 400 F. A desirable operating conditionfor the propane recovery zone for the dewaxed oil is a temperature ofabout 375 F. (bottoms) and a pressure of about 200 lbs. per square inch.The top temperature will vary from about to 160 F.

The phenol recovery zone for the dewaxed oil solution may be operatedunder various temperature and pressure conditions. One mode of operationis to maintain a pressure of about 25 to 100 millimeters (absolute) anda temperature of about 375 F. This temperature, of course, may be variedappreciably as, for example, in a range of about 300 to 500 F. ifdesired.

The wax solution is handled preferably by processing in two propanerecovery zones followed by two phenol recovery zones. The temperaturesand pressures maintained in the respective zones may be variedappreciably depending on other operating conditions. One mode ofoperating the initial propane recovery Zone is to maintain a pressure ofabout 200 lbs. per square inch and a temperature inthe range of 350 to425 F. A satisfactory temperature comprises about 375 F. The secondarypropane recovery zone may be operated at substantially the sametemperature but at a somewhat lower pressure as, for example, about 0 to50 p. s. i. g. The initial phenol recovery zone for the wax solution ispreferably operated under a pressure of 25 to 50 lbs. gauge with a toptemperature in the range of about 420 to 430 F. and at a bottomtemperature of about 550 F. The conditions on the secondary phenolrecovery are similar to the conditions employed with respect to thedewaxed oil solution. The pressures are in the neighborhood of 25 to 100millimeters (absolute) while the temperature is in the range of about350 to 400 F.

The extract-asphalt solution is handled by preferably processing throughtwo propane recovery stages and two phenol recovery stages. Theoperating temperatures and pressures with respect to these stages aresimilar to the operating temperatures and pressures employed withrespect to the recovery of propane and phenol from the wax solution asgiven above.

The propane streams removed from the re-Y spective recovery unit arecombined as well as the phenol streams and handled in a manner asdescribed. This results in unexpected operating advantages and theproduction of high quality products.

Having described the invention, it is claimed:

l. Process for the production of a high quality lubricating oil from adistillate hydrocarbon oil and a higher boiling residuum oil securedfrom a distillation operation and containing asphaltic constituentswhich comprises introducing the distillate oil into the center area of aliquidliquid Vextraction-treater zone, introducing the residuum oil intothe extraction-treater zone below the point of introduction of thedistillate oil, introducing a solvent having a preferential selectivityfor aromatic type constituents as compared to paraflinic typeconstituents into the upper area of said extraction-treater zone,introducing a deasphalting solvent into the lower area of saidextraction-treater Zone below the point of introduction of said residuumoil, withdrawing a solvent extract phase from the bottom of saidextraction-treater zone and separating asphaltic constituents therefrom,withdrawing a raffinate phase comprising parafnic type constituents fromthe top of said solvent treater zone and separating a high qualitylubricating oil therefrom.

2. Process as defined by claim 1 wherein a portion of the solvent havinga preferential selectivity for the more aromatic type constituents ascompared to the more paraiinic type constituents is introduced into saidextractiontreater zone at a point between the point of introduction ofsaid distillate oil and said residuum oil.

3. Process as dened by claim 2 wherein said solvent having apreferential selectivity for said aromatic type constituents as comparedto parainic type constituents comprises phenol and wherein saiddeasphalting solvent comprises liquefied propane,

4. Process as defined by claim 3 wherein said rafnate phase withdrawnfrom the top of said eXtraction-treater zone is treated with saidpropane in a manner to remove waxy constituents therefrom.

5. Process as defined by claim 1 wherein said distillate hydrocarbon oiland said residuum oil are secured by vacuum iiashing a crude oil in amanner to segregate a distillate oil and a residuum oil.

6. Process as defined by claim 5 wherein said distillate oil boils inthe range from about 600 F. to 1100 F. and wherein said residuum oilboils above about 900 F.

7. Process as defined by claim 1 wherein said raflinate phase withdrawnoverhead from said eXtraction-treater zone is cooled whereby a solventrich phase separates, reintroducing said solvent rich phase into saidextraction-treater zone at a point below the point of introduction of 10said solvent having a preferential selectivity for the relatively morearomatic type constituents as compared to the relatively more paralinictype constituents.

8. Process as defined by claim 1 wherein said rainate phase removedoverhead from said extraction-treater zone is handled in a manner tosegregate a dewaxed oil and a waxy solution, and wherein said streams aswell as the extraction solution stream removed from the bottom of saideXtraction-treater zone are handled to segregate the solvent having apreferentialselectivity for the more aromatic type constituents whichstreams segregated are combined and recycled to said eXtraction-treaterzone, and wherein the deasphalting solvent is segregated from therespective streams combined and recycled to the bottom of saidextraction-treater zone.

9. Process as defined in claim 8 wherein said deasphalting solventcomprises propane and wherein said solvent having a preferentialselectivity for the more aromatic type constituents comprises phenol.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,017,432 Bahlke Oct. 15, 1935 2,079,886 Voorhees May 11, 19372,086,487 Bahlke et al July 6, 1937 2,121,323 Manley et al. June 21,1938 2,139,392 Tijmstra Dec. 6, 1938 2,215,359 Livingston et al. Sept.17, 1940 2,225,396 Anderson Dec. 17, 1940 2,248,067 Davis July 8, 19412,258,279 Caselli et al. Oct. 7, 1941 2,270,827 Tijmstra Jan. 20, 1942

1. PROCESS FOR THE PRODUCTION OF A HIGH QUALITY LUBRICATING OIL FROM ADISTILLATE HYDROCARBON OIL AND A HIGHER BOILING RESIDUUM OIL SECUREDFROM A DISTILLATION OPERATION AND CONTAINING ASPHALTIC CONSTITUENTSWHICH COMPRISES INTRODUCING THE DISTILLATE OIL INTO THE CENTER AREA OF ALIQUIDLIQUID EXTRACTION-TREATER ZONE, INTRODUCING THE RESIDUUM OIL INTOTHE EXTRACTION-TREATER ZONE BELOW THE POINT OF INTRODUCTION OF THEDISTILLATE OIL, INTRODUCING A SOLVENT HAVING A PERFERENTIAL SELECTIVITYFOR AROMATIC TYPE CONSTITUENTS AS COMPARED TO PARAFFINIC TYPECONSTITUENTS INTO THE UPPER AREA OF SAID EXTRACTION-TREATER ZONE,INTRODUCING A DEASPHALTING SOLVENT INTO THE LOWER AREA OF SAIDEXTRACTION-TREATER ZONE BELOW THE POINT OF INTRODUCTION OF SAID RESIDUUMOIL, WITHDRAWING A SOLVENT EXTRACT PHASE FROM THE BOTTOM OF SAIDEXTRACTION-TREATER ZONE AND SEPARATING AS-